Colorectal cancer is one of the most frequently diagnosed cancers. Immunotherapy has been proven to be a potential treatment option for colorectal cancer. Colorectal cancer maintains immune escape by expressing low immunogenicity and following the tolerogenic cell death pathway. There is also emerging evidence that oxaliplatin and photodynamic therapy (PDT) can promote anti-tumor immunity. However, the effect of PDT combined with oxaliplatin on colorectal cancer remains elusive. Here, we analyzed the viability of HCT116 and DLD-1 cell lines after treatment with the combination of PDT and oxaliplatin. We found that the viability decreased significantly after the combination treatment. Meanwhile, we also detected that sinoporphyrin sodium (DVDMS)-derived PDT could amplify oxaliplatin-induced immunogenic cell death (ICD) in different colorectal cancer cell lines. More importantly, the combination of DVDMS-derived PDT and oxaliplatin presented strong immunogenic potential in immunocompetent BALB/c mice in the vaccination assay. Taken together, our data demonstrated that the combination of DVDMS-derived PDT and oxaliplatin is a potential novel therapy for colorectal cancer.

中文翻译：

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光动力疗法增强奥沙利铂诱导的结直肠癌免疫原性细胞死亡

结直肠癌是最常诊断的癌症之一。免疫疗法已被证明是结直肠癌的潜在治疗选择。结直肠癌通过表达低免疫原性并遵循耐受性细胞死亡途径来维持免疫逃逸。还有新的证据表明奥沙利铂和光动力疗法（PDT）可以促进抗肿瘤免疫。然而，PDT联合奥沙利铂对结直肠癌的疗效仍不清楚。在这里，我们分析了 PDT 和奥沙利铂联合治疗后 HCT116 和 DLD-1 细胞系的活力。我们发现联合治疗后活力显着下降。同时，我们还检测到中华卟啉钠（DVDMS）衍生的PDT可以放大不同结直肠癌细胞系中奥沙利铂诱导的免疫原性细胞死亡（ICD）。更重要的是，在疫苗接种测定中，DVDMS 衍生的 PDT 和奥沙利铂的组合在免疫功能正常的 BALB/c 小鼠中表现出强大的免疫原性潜力。总而言之，我们的数据表明，DVDMS 衍生的 PDT 和奥沙利铂的组合是一种潜在的结直肠癌新疗法。